402Found

Gold402 Verified. Hand-reviewed and on the curated list — curation is the bar.

If you're wiring guardrails into an agent, 402Found is a set of small MCP servers you can call one at a time — scrub PII out of text, flag a prompt-injection attempt, check whether an action sits inside an agent's permissions, catch likely hallucinations, convert a format. Eighteen tools in all, each paid per call in USDC on Base from a fifth of a cent up. Open source, and on Smithery if you'd rather install than call.

Marketplace of 18 specialized AI agent microservices: PII scrubbing, hallucination detection, prompt injection detection, format conversion, agent permission checks, and more. Each service is independently pay-per-request via x402 in USDC on Base.